1. Field of the Invention
This invention generally relates to an anchor for securing cargo, using metal banding, onto railway cars including flatcars, center beams, gondolas and log cars. An assembly comprising an interlocking retainer and link is used to decrease the occurrence of banding breakage. The enhanced radius of the link provides a greater load bearing area for engaging the banding, thereby reducing the stress present in the banding when securing heavier and/or top-heavy loads, such as steel pipe. Special application is found for this approach in securing heavy loads transported by flatcar.
2. Description of Related Art
Heavy loads, such as steel pipe and the like, can be transported in a number of ways, including by flatcar. In order to prevent the cargo from becoming damaged, it is necessary to provide securing means. Various known securing means include plastic strapping, cord strapping, and steel banding. The preferred way to secure a heavy load is to bind it with a plurality of steel bands or straps. In practice, each band is connected to the floor or side frame of the flatcar by an anchor assembly at opposite sides of the cargo. Once the band is connected to the anchors and tightened, a crimp seal typically is applied to maintain an appropriate tension level during transport.
Many types of anchor assemblies are well-known. The “Flexi” anchor assembly made by Ireco LLC is an example of a known device. FIGS. 1-4 illustrate a device 20 according to the two-piece “Flexi” anchor assembly. The “Flexi” assembly 20 comprises a steel retainer 22 which is affixed to the floor or frame 24 of a flatcar and a steel link 26 which is movably connected to the retainer 22. The arcuate retainer 22 takes the form of an inverted “U” which can be welded to the floor or frame 24 of the flatcar. The link 26 is triangular and defines a generally triangular central aperture 28 which interlocks the retainer 22. The anchor assembly 20 is configured such that the retainer 22 passes through the central aperture 28 of the link 26 and effectively hooks the link 26 to a floor surface or a frame area 24 of the flatcar.
One side 30 of the link 26 includes a banding portion 32, while the end 34 defined by the intersection of the other two sides 36 engages the retainer 22. FIGS. 1 and 2 show that the banding portion 32 includes a lateral convex curvature surface 38 facing the central aperture 28. This part of the banding portion 32 has a radius of curvature “R” of approximately five inches. FIGS. 3 and 4 show that the cross section 40 of the retainer-engaging end 34 is circular, while the cross section 42 of the banding portion 32 approximates a rectangle with curved corners. The two corners 44 nearest the central aperture 28 have a 0.25 inch radius of curvature “r”.
In use, a securing means, such as a steel band 46, is passed through the aperture 28 of the link 26, so as to engage the banding portion 32. Banding surface 38 is sufficiently wide to accept a 1.25 inch or 2 inch steel band. When tension is applied to the steel band 46, it tightens against the banding portion 32 and deforms in part to take the shape of the lateral convex curvature surface 38. FIG. 2 shows in broken lines that the link 26 is free to take an angled orientation when the steel band 46 engages the banding surface 38. FIG. 2 also shows in broken lines the use of a cable or wire 48 extending from an end of the link between two sides 30 and 36.
The steel band 46 engages a portion of the cross-sectional perimeter of the banding portion 32 of the link 26, best shown in broken lines in FIG. 3. The surface of the banding portion 32 along the link 26 generally conforms to the opposing, parallel surfaces 50 of the link 26 and the lower surface 52. The magnitude of the curvature of the steel band 46 about the banding portion 32 is referred to herein as the banding radius “r”. It can be seen that the banding radius “r” in FIG. 3 varies due to the irregular shape of the banding portion 32. The lower curved corners 44 each subject the steel band 46 to a relatively sharp curve, which can result in creasing of the steel band 46. FIG. 3 also shows the link 26 flat against the floor surface 24 of the flatcar, in a stored position when it is not in use.
It will be appreciated that a large tensile force must be applied to the steel bands in order to secure the cargo. One problem associated with prior art anchor assemblies which we now have determined to be important is that, when the steel bands are subjected to such large tensile forces, especially when combined with forces that result from even slight shifting of lading weight during the rocking movement of rail transport, there is the possibility that metal fatigue will cause the bands to fail. The movement of rail transport can cause repetitive back and forth bending at locations where the banding engages a corner or tight radius.
We have determined that the banding radius of anchor assemblies as illustrated in FIGS. 1-4 is inadequate, especially when used to secure top-heavy or uneven loads, such as a load of steel pipes, the steel band can become creased along the curved corners of the banding portion, which creases are subjected to dynamic bending forces over time and subsequently break. This is especially problematic when the cargo must be transported a great distance. The steel band can withstand only a certain stress level and will deform and fail once that level is exceeded. It is thought that the critical stress level decreases due to the combination of creasing, dynamic bending forces, and metal fatigue associated with prior art anchor assemblies. As large tensile forces are required to safely secure heavier loads, and as heavy unbalanced loads need to be transported by rail over long distances, an anchor assembly which reduces the risk of band breakage is needed.
FIGS. 5 and 6 illustrate examples of previous attempts to solve these band breakage problems. As shown, both anchors 56 and 58 provide a right cylindrical element 60 having a larger banding portion than that illustrated in FIGS. 1-4, while also providing an increased banding radius. The cylindrical element 60 is separate from the link body 62 and mounted thereto by a bolt 64, which is itself secured to the link body 62 by a threaded nut 66.
It will be appreciated that, in lading anchors for steel bands, the stress in the steel band is inversely proportional to the area of the band which engages the banding portion of the link. Hence, for a given tensile force applied to the steel band, a larger area of engagement between the band and the banding portion of the anchor will allow for a greater force distribution, which decreases the stress to which the steel band is subjected. An increased banding radius (perpendicular to the axis of a right cylinder such as element 60 of FIGS. 5 and 6) is also desirable because it reduces the risk of creasing the steel band which, when combined with dynamic bending forces, leads to metal fatigue and eventually failure at heavier loads. Accordingly, the anchor assemblies of FIGS. 5 and 6 attempt to decrease band breakage by providing a larger banding portion and right cylindrical banding radius. The anchor assemblies of FIGS. 5 and 6 are relatively expensive because they require several components (i.e. a cylinder, a bolt, and a nut) to achieve their goal.
Accordingly, a general object and aspect of the present invention is to provide an improved anchor assembly for use with a railway car such as a flatcar, a center beam car, a gondola car, a log car and the like.
Another object or aspect of this invention is to provide an improved anchor assembly which reduces the risk of band breakage for heavier loads and those having an unbalanced or high center of gravity without increasing the number of components of a current anchor assembly.
Another object or aspect of the present invention is to provide an improved anchor assembly and method that address metal banding breakage problems for top-heavy lading loads, including those encountered during long-distance rail transport.
Other aspects, objects and advantages of the present invention, including the various features used in various combinations, will be understood from the following description according to preferred embodiments of the present invention, taken in conjunction with the drawings in which certain specific features are shown.